Disposable fire extinguisher

ABSTRACT

A disposable fire extinguisher designed for permanent mounting within a selected area at a point where fire may be likely. Fire extinguishing fluid is housed within a hermetically sealed container having a discharge tube defining a discharge orifice extending therefrom. The discharge orifice is closed by a cap which is held in place with a fusible metal alloy. Upon subjection to continued elevated temperature, as would exist from a fire within the selected area, the fusible metal alloy becomes substantially liquid and the high pressure of the fire extinguishing fluid within the container blows the cap free of the tube thus permitting the contents of the container to freely discharge through the discharge orifice into the selected area thereby extinguishing the fire.

United States Patent [1 1 Linsalato et al.

DISPOSABLE FIRE EXTINGUISHER Inventors: Oronzo L. Linsalato, San Marino;

Edward Pesout, Jr., Newbury Park, both of Calif.

Assignee: Textron Inc., Providence, RI.

Filed: Aug. 5, 1974 Appl. No.: 494,694

References Cited UNITED STATES PATENTS 11/1955 Hicks 169/26 6/1956 Deyo.... 169/26 4/1974 Poitras 169/26 X 8/1974 Lockwood 169/26 X [4 1 Sept. 23, 1975 Primary Examiner-M. Henson Wood, Jr.

Assistant Examiner-Michael Mar Attorney, Agent, or Firm-Nilsson, Robbins, Bissell, Dalgarn & Berliner [57] ABSTRACT A disposable fire extinguisher designed for permanent mounting within a selected area at a point where fire may be likely. Fire extinguishing fluid is housed within a hermetically sealed container having a discharge tube defining a discharge orifice extending therefrom. The discharge orifice is closed by a cap which is held in place with a fusible metal alloy. Upon subjection to continued elevated temperature, as would exist from a fire within the selected area, the fusible metal alloy becomes substantially liquid and the high pressure of the fire extinguishing fluid within the container blows the cap free of the tube thus permitting the contents of the container to freely discharge through the discharge orifice into the selected area thereby extinguishing the fire.

7 Claims, 5 Drawing Figures US Patent Sept. 23,1975

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FIG.5.

DISPOSABLE FIRE EXTINGUISHER BACKGROUND oF THE INVENTION 1. Field of the Invention The invention relates-to a disposable fire extinguisher particularly suitable for use in enclosed areas.

2. Description of the Prior Art There are many types of prior art disposable or portable fire extinguishers which automatically operate in response to a rise in ambient temperature resulting fromthe presence of a fire. Such fire extinguishers rely upon the melting of a plug, fusible solder around a cover, or a band of fusible material or the like to effect discharge of the fireextinguishing fluid under pressure into the desired area. Such prior art apparatus is not re liable in all cases in that they have been shown not be consistently responsive to a specific predetermined temperature or'range of temperatures. Thus, such prior fire extinguishers do not immediately and efficiently detect the presence of a fire and responsive thereto exhaust the fire extinguishing fluid automatically and reliably, while at the same time providing apparatus which may be disposed of once the fluid has been discharged therefrom. The prior art known to applicant consists of US. Pat. Nos. 231,713; 458,171; 1,348,565; 1,162,020; 2,293,366; 2,560,468; 3,536,139 and 3,664,430.

SUMMARY OF THE INVENTION A fire extinguisher including a sealed container housing fire extinguishing fluid under pressure. A discharge tube is sealed at one end of the container and at the opposite end is closed by a thermally responsive means which becomes fluid upon application of heat thereto to release and discharge the fire extinguishing fluid from the container.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT lnFIG. l, a fire extinguisher l constructed in accordance with the principles of the present invention is shown mounted within an enclosed container 12 such for example as may be utilized for containing trash 14.

The trash 14 is aflame as shown at 16 and the flame has activated the fire extinguisher thereby causing the fluid contained therein to be discharged as illustrated at 18 into the interior of the container 12 to thus extinguish the flame. 'As will be more fully explained hereinafter, upon visual inspection, the discharge of the contents of the extinguisher will be detected and the extin-' guisher then removed, disposed of and replaced by a new fully charged fire extinguisher.

A fire'extinguisher as constructed in accordance with the principles of the present invention may have many uses wherever combustible material is collected in a relatively enclosed area. Typical uses for such a fire extinguisher are on boats, in campers, trailers, motorhomes, andin enclosed places in homes or offices where trash materials or combustible materials are stored or collected, such as vaults, safes, mail storage areas, paint lockers, and the like. The fire extinguisher of the present invention has particular utility in waste receptacles of aircraft and the example descriptive of the present-invention and its particular construction will be given'with respect tosuchan application.

Referring now particularly to FIGS. 2, 3 and 4, the fire extinguisher l0 constructed in accordance with the present invention includes a container 20 having a mounting bracket 22 secured thereto. The bracket 22 defines openings 24 and 26 by which the extinguisher 10 may be secured inplace as desired by appropriate screws, bolts, or the like (not shown). A pair of discharge tubes 30-and 32 are secured at one end 34 and 36, respectively, thereof to the surface of the container 20 and at the opposite ends 38 and 40 thereof define a discharge orifice. Each of the tubes-30 and 32 is coonstructed in such a way that the orifice portion thereof is remotely disposed from the container 20 and the tube is coiled as shown at 42 and 44, repsectively, to take up that portion of the tubes that would otherwise extend from the container 20 if the tubes 30 and 32 were not coiled. However, for purposes of the inverttion (as will be more fully explained hereinafter), it is immaterial whether the tube is coiled, spiraled, zigzagged, or left completely straight and any particular configurationmay be utilized as is desired, depending upon the particularapplication and available space- The discharge .tubes may be passed through a wall to allow the fire extinguishing fluid to be discharged into aspace remote from the area where the container is mounted or alternatively to have one container with two discharge, tubes, onein each of two different areas.

In any event, the orifice ends of the discharge tubes must be disposed within the area to be protected so as to sense undesired temperature rises and responsive thereto to discharge the fire extinguishing fluid.

The container 20 is charged with a fire extinguishing material which is typically one of a familyof halogenatedcompounds used for this general purposes. The compound .mostoften used and the one preferred is bromotrifluoromethane (CBrF The container 20 is charged with the fire extinguishing material of the desired type through a filling tube 50 until the desired amount of material is contained therein. Thereafter the tube 50 is pinched off as shown at 52 and sealed at its terminal point 53 with the requisite amount of the fluid in the container 10 as illustrated at 54. Thestorage pressure of the material will typically be somewhere between 25 pounds per square inchand 740 pounds per square inch, depending upon the ambient temperature (between 30F and +F). However, the storage pressure may, with the same type of material but higher temperatures, exceed 1,300 psi.

The container 20 may be constructed of any material desired which will withstand the internal pressures generated. However. it has been determinedthat an appropriate material is steel and the same may be formed into a pair of'container halves as'shown at 56 and 58. The container halves may be mated as illustrated at 60 and brazed to form a hermetically sealed container.

The filling tube 50 and the tubes 30 and 32 may each also be brazed to the container to provide a hermetic seal.

As illustrated in the drawings, the discharge end 38 and 40 of the tubes may be disposed in any particular direction as desired depending upon the particular application to which the extinguisher is to be put. Such positioning may be accomplished .during the construction of the device when the coils are being formed or alternatively such positioning may occur upon installation of,the.extinguisher within the desired location. Under certain conditions, it has been determined that the discharge tubes 30 and 32 should not be bendable subsequent-to installation of the device. As a result, the discharge tubes may be constructed in such a way that the lower end portion thereof as shown at 62 is constructed of a relatively rigid material such as brass while the remainder of the tube such as shown at 64 may be constructed of a relatively malleable material such', .for example, as copper. A brass sleeve 66 may then be inserted in place 'over the two portions of the tubeand brazed to retain the hermetic integrity of the structure while providing a relatively rigid end portion to the discharge tube.

Theorificeend of the discharge tubes are closed by a cap 70 which functions to retain the fire extinguishing material within the container without leakage. The cap 70 also functions as a valve in that upon sensing the presence of fire, the cap 70 is released to permit automatic discharge of the fire extinguishing material 54 from the container 20. Thereafter, the cap too may function as an indicator that the fire extinguisher has been discharged. The cap 70 is maintained in place by a fusible alloy material 72 which is sandwiched between the cap 70 and the tube 74 as illustrated particularly in FIG. 5. This fusible alloy material 72 may be any material desired depending upon the particular application so long as it will melt or become relatively fluid when subjected to application of elevated temperature thereto for a predetermined time. Upon the fusible alloy material becoming relatively liquid, the pressure of the fire extinguishing fluid contained within the container acting against the end of the capas indicated by the arrow 76 will force the cap from the tube thereby opening the discharge orifice to permit automatic expulsion of the fire extinguishing fluid from the container 20. Several examples of fusible alloys which may be used are as follows:

Melting Bi. '7: Pb. Sn. Cd. 71' In. Temperature (l) 50.00 26.70 13.30 10.00 l58l58 (2) 57.00 l7.00 26.00 l74l74 (3) 52.50 32.00 l5.50 203-203 (4) 54.00 26.00 20.00 2l6-2l7 (5) I 55.50 44.50 255-255 It has been discovered byapplicants that the discharge tube must be of sufficient length to position the cap a sufficient distance from the body of the fire extinguishing fluid 54 to remove the same as a heat sink. If the cap 70 is sufficiently close to the body of fluid 54, the fusible alloy does not become fluid within a reasonable time due to heat loss by convection and conduction through the discharge tube.

It has been found in some'instances that it is difficult to visually detect the presence or absence of the cap 70 on the end of the discharge tube. As a result, a visual indicator sleeve 78 may be used if such is desired. The sleeve 78 is loosely slipped over the tube 74 and is press-fitted over the end of the cap 70 as is illustrated at 80. The press-fit however is such that in the event the indicator tube 78 in any way becomes bound or caught upon the tube or surrounding portions of the apparatus in which the fire extinguisher is mounted, the cap 70 can slip from the indicator sleeve 78 thus providing no interference with the discharge of the fire extinguishing fluid from the container 20. it has been found that the indicator tube 78 may be made of Teflon with excellent results.

What is claimed is:

1. Fire extinguisher comprising:

A. a sealed container for housing a fire extinguishing fluid under pressure;

B. a discharge tube sealingly secured at one end to said container and communicating with the interior thereof;

C. closing means including a cap over the other end of said tube disposed remote from said container and closing said tube to prevent discharge of said fluid from said container during normal conditions;

D. thermally responsive means sandwiched between said cap and said tube securing said closing means to said discharge tube, said thermally responsive means becoming fluid upon application of heat thereto for a predetermined time thereby to release said closing means and discharge said fluid from said container; and

E. said discharge tube having a predetermined length sufficient to position said closing means remote from the bulk of fluid in said container by an amount to preclude said fluid from conducting heat by convection and conduction through said fluid away ifrom said thermally responsive means and precluding release of said closing means within said predetermined time.

2. Fire extinguisher as defined in claim 1 which further includes indicator means affixed to said cap and said tube, said indicator means being removed with said cap thereby to provide an indication that the fluid contents of said container have been discharged.

3. Fire extinguisher as defined in claim 2 wherein said indicator means is a sleeve loosely fitting over said tube and affixed to said cap by a fit such that in the event said sleeve becomes bound on said tube said cap will part from said sleeve.

4. Fire extinguisher means as defined in claim 1 wherein said discharge tube and said cap are constructed of thermally conductive metal and said thermally responsive means is a fusible metal alloy.

5. Fire extinguisher as defined in claim 4 wherein said tube is coiled to provide said sufficient length to remotely position said cap but allow said cap to be disposed adjacent said container.

section, affixed to said container, being of malleable material, the remainder of said tube being of relatively rigid material thereby to reduce likelihood of bending said tube after installation of said extinguisher. 

1. Fire extinguisher comprising: A. a sealed container for housing a fire extinguishing fluid under pressure; B. a discharge tube sealingly secured at one end to said container and communicating with the interior thereof; C. closing means including a cap over the other end of said tube disposed remote from said container and closing said tube to prevent discharge of said fluid from said container during normal conditions; D. thermally responsive means sandwiched between said cap and said tube securing said closing means to said discharge tube, said thermally responsive means becoming fluid upon application of heat thereto for a predetermined time thereby to release said closing means and discharge said fluid from said container; and E. said discharge tube having a predetermined length sufficient to position said closing means remote from the bulk of fluid in said container by an amount to preclude said fluid from conducting heat by convection and conduction through said fluid away from said thermally responsive means and precluding release of said closing means within said predetermined time.
 2. Fire extinguisher as defined in claim 1 which further includes indicator means affixed to said cap and said tube, said indicator means being removed with said cap thereby to provide an indication that the fluid contents of said container have been discharged.
 3. Fire extinguisher as defined in claim 2 wherein said indicator means is a sleeve loosely fitting over said tube and affixed to said cap by a fit such that in the event said sleeve becomes bound on said tube said cap will part from said sleeve.
 4. Fire extinguisher means as defined in claim 1 wherein said discharge tube and said cap are constructed of thermally conductive metal and said thermally responsive means is a fusible metal alloy.
 5. Fire extinguisher as defined in claim 4 wherein said tube is coiled to provide said sufficient length to remotely position said cap but allow said cap to be disposed adjacent said container.
 6. Fire extinguisher as defined in claim 5 which includes a plurality of discharge tubes, the discharge ends thereof being directed in different directions.
 7. Fire extinguisher as defined in claim 4 wherein said discharge tube is constructed of two sections, the first section, affixed to said container, being of malleable material, the remainder of said tube being of relatively rigid material thereby to reduce likelihood of bending said tube after installation of said extinguisher. 